[clang-tidy] misc-include-cleaner reports <new> unused for placement new

`misc-include-cleaner` reports `` as unused in a file whose only use of it is a
placement-new expression. Following the advice makes the file fail to compile, and clang's
own diagnostic names the very header the check wants removed.

The reference is to `operator new(std::size_t, void*)`, which is declared in ``. It
appears to be missed because a placement-new expression is an operator call rather than a
named symbol reference, so nothing in the file points at ``. The missing-includes half
is consistent with that reading: with `` deleted it does not ask for a provider either.

### Version

```
$ clang-tidy --version
LLVM (http://llvm.org/):
LLVM version 22.1.8
Optimized build.
```

Installed from PyPI (`clang-tidy==22.1.8`). Reproduced on macOS with libc++.

### Reproducer

`new_repro.cc`:

```c++
#include
#include

struct T { int x; };

int f(void *storage) {
T *t = new (storage) T{1};
return t->x;
}
```

`.clang-tidy`:

```yaml
Checks: '-*,misc-include-cleaner'
CheckOptions:
- key: misc-include-cleaner.MissingIncludes
value: 'false'
```

A compilation database is required for the check to run; `--` on the command line is not
enough (with `--` the check silently reports nothing at all, including for a deliberately
unused header).

```
$ clang-tidy -p . --quiet new_repro.cc
new_repro.cc:2:1: warning: included header new is not used directly [misc-include-cleaner]
```

### Expected

No diagnostic. `` is used: it provides the `operator new(std::size_t, void*)` overload
that the placement-new expression resolves to.

### Why this one bites

Acting on the suggestion breaks the build, and clang says so explicitly:

```
$ clang++ -std=c++20 -fsyntax-only new_repro_without_new_include.cc
error: no matching 'operator new' function for non-allocating placement new expression;
include
6 | T *t = new (storage) T{1};
| ^ ~~~~~~~~~
```

So the front end already knows the requirement and names the header; the information does
not reach the check.

### Possibly related

#64191 is the same shape for a different operator — `` was reported unused because
`operator|` in range-adaptor composition was not tracked.

Start with new_repro.cc, its .clang-tidy configuration, and the clang-tidy command shown in the report; confirm the warning with a compilation database. Trace misc-include-cleaner's handling of placement-new and operator calls, using the related ranges operator issue (#64191) for comparison. Done means the check no longer reports as unused while the existing compilation behavior remains valid.

Written by the indexing model from the issue text.